In general, a page-wide array printer comprises a substrate transport path and a print head or array of print heads extending the full width of the substrate transport path. Such an arrangement allows the entire width of a substrate to be printed simultaneously. A substrate may be any sort of sheet-like medium, including paper, cardboard, plastic and textile.
The print head or array of print heads is usually fixed within the printer, and a substrate on which an image is to be printed is moved past the print head or heads along the substrate transport path. A complete image is often printed in a single printing pass.
In such single-pass printing image quality may sometimes be limited. For example, if the image requires a large amount of ink to be transferred to part or all of the substrate, that part of the substrate may warp or become deformed due to receiving a high flow of liquid ink in a short time. It is also possible that ink from adjacent print head nozzles may coalesce, causing the image to become blurred, or to appear grainy. It can be difficult to achieve detailed images that are also sharp in single-pass print-modes.